Mechanically workable alloy



Patented July 2, 1935 UNITED STATES PATENT OFFICE 2,006,599 MECHANICALLY wonxannn ALLOY No Drawing. Application June so, 1933, serial 6 Claims.

This invention relates to a process for. the pro- In Austria July 8, 1932 for the purposes of the present invention, the

duction of articles which have to fulfill the reparts being given by weight:-

quirements of being resistant to corrosion and capable of being mechanically worked, such as for 5 example, boiling vessels and castings such as fittings (valves and the like) and so forth.

It is known from the literature that gamma brass, that is to say copper-zinc-alloys containing from 31 to 40% of copper is more resistant to corrosion than the brass alloys usually employed which belong to the alpha and alpha+beta fields and contain for example, 68 to 72% of copper.

It is, however, impossible to employ the gamma alloys industrially on a technical scale because said alloys are extraordinarily hard and brittle and are consequently unworkable.

It has now however, been unexpectedly ascertained in accordance with the present invention, that copper-zinc-alloys of the beta+gamma field,

i. e. copper-zinc-alloys containing about 40 to 50% of copper, constitute a corrosion-resistant structural material for machines and machine parts which is at the same time mechanically workableand by virtue of these properties, suitable for the manufacture of articles which are required to resist corrosion but must nevertheless undergo a mechanical working.

An example of an alloy fulfilling these requirements is one containing 44% of copper and 56% of zinc. The copper content of these binary alloys should preferably not fall below 43%.

The workability of said alloys can be increased by adding thereto small quantities of cobalt or nickel and preferably nickel and cobalt jointly, the amounts of such added metals being less than 10% and preferably less than 6%. When adding such metals, the copper content of the alloy can be reduced down to the limits of the 40 gamma field.

The following are examples of alloys suitable Remainder zinc. 5

46.0% of copper 3.0% of cobalt Remainder zinc.

45.0% of copper 2.0% of nickel 10 2.5% of cobalt Remainder zinc.

What we claim is:

1. Corrosion-resistant, mechanically workable alloys which consist substantially of a copperzincpalloy containing copper in an amount corresponding to beta+gamma, brass and an addition of from 2 to 10 percent of one of the elements nickel and cobalt.

2. Corrosion-resistant, mechanically workable 20 alloys according to claim 1, wherein the zinc is present in an amount above 50 percent.

3. Corrosion-resistant, mechanically workable alloys according to claim 1, containing 3' to 4 percent cobalt.

4. Corrosion-resistant, mechanically workable alloys according to claim 1, containing 3 to 4 percent of nickel.

5. A corrosion-resistant and mechanically workable alloy having the following composition: 43.0 per cent. copper, 4.5 per cent. nickel, and the remainder zinc.

6. A corrosion-resistant and mechanically workable alloy having the following composition: 35 46.0 per cent. copper, 3.0 per cent cobalt, and the remainder zinc.

WOLF JOHANNES MULLER. MORITZ NIESSNER. 

